Summertime has arrived with a vengeance in much of Europe. The continent is shimmering in a blistering heat wave that is worrying farmers and power companies. And the situation is especially serious in Italy, where officials were holding a crisis meeting Wednesday to determine whether or not they should impose a state of emergency.

Italians have been warned that, if it does not rain before the end of the month, they should expect power cuts and water rationing.

Guido Bertolaso, who heads Italy's Civil Protection Department, says water supplies will only last for another two weeks unless drastic measures are taken.

"It's quite serious. Every year we face such problems. But I must say that, now, the problems are increasing, and we don't have problems only with drinking water but we also have problems with the supply of water for agriculture and for our industrial sector," he said.

The country's biggest river, the Po, which crosses northern Italy from west to east, has dropped to its lowest levels in nearly 100 years, bringing all water traffic to a standstill. Farmers in the Po Valley, which is Italy's breadbasket, have been battered by weeks of drought. And power plants along the river lack the water they need to cool their turbines. Meteorologists predict the record temperatures and the lack of rain will continue well into August.

Italian newspapers are warning that fruit and vegetable prices could increase by 30 percent because output from parched fields is shrinking. Officials now have to decide whether scarce water resources should be used to irrigate crops or keep factories producing.

The country's power grid is also under strain. It is struggling to keep up with higher-than-usual demand caused primarily by the use of air conditioners. Andrea Bolling, a spokesman for the national electric company, says his firm may have to impose blackouts to protect the system from breaking down.

"It's a possibility we cannot remove from our horizon at the moment. However, we are fighting with all our competence and enthusiasm to try to avoid it," he said.

Elsewhere in Europe, northern cities like Brussels and Berlin have been basking this week in uncommonly warm weather to the delight of natives and visitors alike. In Paris, temperatures reached 35 degrees centigrade on Wednesday. Purveyors of bottled water and ice cream vendors did brisk business, and weary tourists used the city's fountains as wading pools.

But there are signs that the balmy weather, at least in northern Europe, is on its way out. Violent storms lashed western France overnight, killing four people. In London, the sunshine and warm temperatures that delighted citizens earlier in the week gave way to rain and a cool breeze on Wednesday. And forecasts say that, over the next two days, thunderstorms are expected to gradually spread through much of the continent, although southern Europe will remain parched and dry.